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Marthor
11-21-2012, 9:34 AM
This topic comes around now and then and I've read several threads, but I just thought of a new way to think about it that makes sense.

I've read enough threads and done some calculations, to say that a 45 acp has knockdown power similar to an 80 mph fastball... which isn't that much "knockdown power". Knockdown power is generally a myth.

The new way to think about it though is "for every action, there is an equal and opposite reaction". If you fire a weapon that knocks you back on your butt, then yes, that probably has some real "knockdown power". But that's going to be something like an elephant gun, that is hard to manhandle the kickback.

Just thought I'd share. Knockdown power makes more sense to me thinking about it that way. Cheers! :cool:

Marthor
11-21-2012, 9:39 AM
You can also imagine that if a 45 acp is like an 80 mph fastball, then the recoil is also similar to catching an 80mph fastball in your hands.

Having fired enough 45 ACP and also having cought enough baseballs and softballs, I can imagine and agree that they are pretty close in the force felt.

paul0660
11-21-2012, 9:46 AM
Huh?

Having fired enough 45 ACP and also having cought enough baseballs and softballs, I can imagine and agree that they are pretty close in the force felt.
__________________

Uh..........no. Don't stop thinking about it!

Mr310
11-21-2012, 9:48 AM
Now are we talking a .45 hardball or a .45 HJP?




:43:

Marthor
11-21-2012, 9:49 AM
Huh?
Uh..........no. Don't stop thinking about it!

So, what do you imagine in your head? Do you think that the recoil from a 45 is greater than catching an 80mph fastball? LOL

I suggest you go catch one.

TheExiled
11-21-2012, 9:52 AM
I havent felt a .45ACP that felt like a 80mph fastball

paul0660
11-21-2012, 10:01 AM
So, what do you imagine in your head? Do you think that the recoil from a 45 is greater than catching an 80mph fastball? LOL

I suggest you go catch one.

I think the better test would be getting hit in the chest by a fastball. I have felt that, and am pretty sure I prefer it to the .45.

Set a date and we can compare. On you.

Marthor
11-21-2012, 10:03 AM
I havent felt a .45ACP that felt like a 80mph fastball

When you fire your 45 acp gun, you already have a firm grip on the handle.

When you catch the 80mph fastball, you have to eliminate the sting and focus only on how much push force you got from catching it. That's the knockdown power.

Marthor
11-21-2012, 10:06 AM
I think the better test would be getting hit in the chest by a fastball. I have felt that, and am pretty sure I prefer it to the .45.

Set a date and we can compare. On you.

The topic is knockdown power. Your question is about the effects besides knockdown power. The bullet has smaller surface area and greater speed so it will penetrate. The better test is to eliminate the penetration to focus on the knockdown power.

Wear a steel plate on your chest. The force felt will be similar.

sjm9877
11-21-2012, 10:41 AM
I wish they made a caliber that had the same knock down power as Chuck Norris.

BonnieB
11-21-2012, 10:45 AM
If you're going to do it, buy a Smith &Wesson Model 500.

I saw a guy shooting one at the range yesterday. Talk about PUNCH !

ROCKETW19
11-21-2012, 10:47 AM
The topic is knockdown power. Your question is about the effects besides knockdown power. The bullet has smaller surface area and greater speed so it will penetrate. The better test is to eliminate the penetration to focus on the knockdown power.

Wear a steel plate on your chest. The force felt will be similar.

I am not into the whole knock down power thing as all the paper targets I shoot always seem to get holes in them

BUT when I read this it made sence to me. instead of plate lets make it a vest so you can really feel it. by the way I will watch or film thats about it,lol

zfields
11-21-2012, 10:59 AM
http://d2tq98mqfjyz2l.cloudfront.net/image_cache/1332787583877423.jpg

ClarenceBoddicker
11-21-2012, 12:39 PM
Don't waste your time trying explain to people on here basic known scientific facts like Newton's laws. They have it firmly set in their minds from watching Hollywood TV shows & movies, that .40 and up pistol rounds posses tremendous knock down power. Powerful enough to lift you off your feet & throw you backwards. Enough power to toss around a 250lb person, yet can somehow be easily fired with one hand. They also wrongly believe that hollow point rounds enhance knock down power.

In the real world you can watch Richard Davis get shot with pistols, shotguns & rifles multiple time while wearing his 2nd chance vests, even while standing on one foot & not get thrown to the ground. The movie to watch with those scenes is called: Deadly Weapons: Firearms & Firepower from 1985.

o5f1Fo4r4_I

luchador768
11-21-2012, 12:56 PM
80mph isn't a "fastball.". More like an off speed breaking ball.

gsparesa
11-21-2012, 2:05 PM
So, I should be using a bat on the perp instead of my 629?

Distro
11-21-2012, 2:16 PM
If catching an 80mph "fastball" feels like the recoil of a handgun then that truly is limp wristing.

hundreddollarman
11-21-2012, 2:16 PM
Next time someone talks about "this caliber is better than that one blah blah blah," maybe they should get shot in the knees and tell us which one hurts more. Just my thinking.

Sheepdog1968
11-21-2012, 3:53 PM
People have died from 22's. People have lived from shotgun slugs. All bets are off. The most important thing is to be able to hit your target under stressfull conditions all the time. That takes lots of practice. Find a caliber you like (ideally somewhere along the 38, 357, 9 mm, 10 mm, 40, 45 caliber lines) and practice a lot. Other than that, I tend not to worry about all the formulas to calculate what is best as you will never arrive at a single answer or enlightenment.

Cato
11-21-2012, 4:03 PM
There's no such thing as "knock down" power from guns. Bullets are TINY. When they hit it's similar to getting stabbed with an icepick. Your goal should be to "stab" a vital organ, not "run" someone over with a Mack truck.

JMP
11-21-2012, 4:12 PM
This topic comes around now and then and I've read several threads, but I just thought of a new way to think about it that makes sense.

I've read enough threads and done some calculations, to say that a 45 acp has knockdown power similar to an 80 mph fastball... which isn't that much "knockdown power". Knockdown power is generally a myth.

The new way to think about it though is "for every action, there is an equal and opposite reaction". If you fire a weapon that knocks you back on your butt, then yes, that probably has some real "knockdown power". But that's going to be something like an elephant gun, that is hard to manhandle the kickback.

Just thought I'd share. Knockdown power makes more sense to me thinking about it that way. Cheers! :cool:

dafuq--can you show us your calculations? How did you arrive at this conclusion. The 80 mph's angular momentum and rotational inertia may vary significantly if the pitcher's has a cross-seam or with-seam grip.

AeroEngi
11-21-2012, 4:15 PM
Actually, if you're looking at it from a momentum standpoint (recoil = momentum = knockdown power), a 230gr projectile with velocity of 850 ft/s is more like a baseball with a velocity of 61 mph.

The average baseball weighs around 142 grams which converts to about 2,187 grains. 61 mph converts to 89.47 ft/s. Multiply them together and you get 195,643 grains*ft/s.

For the bullet, a 230 gr projectile at 850 ft/s gives you a momentum of 195,500 grains*ft/s.

AeroEngi
11-21-2012, 4:15 PM
Don't know why it double posted.

vliberatore
11-21-2012, 4:22 PM
Hmm..and I've caught 80mph with my bare hands...

Who wants to come over so we can try .45 ACP?

mjmagee67
11-21-2012, 4:30 PM
Shot placement, shot placement, shot placement!

SJgunguy24
11-21-2012, 4:43 PM
Bullets kill one of 3 ways, shock, trauma, and blood loss. They all do the same thing. People get hit with handguns and run or keep fighting. Unless you hit the pump center, nerve center, or shatter a weight bearing bone, your still in a fight.
The biggest difference with rifles is the amount of damage done do to velocity and bullet design. There is no knock down power with handguns.
Google Jennifer Fulford-Salvano, she took 10 handgun rounds, 3 were stopped by her body armor. That's 7 hits and she kept fighting and killed 2 men.

Marthor
11-21-2012, 4:53 PM
Actually, if you're looking at it from a momentum standpoint (recoil = momentum = knockdown power), a 230gr projectile with velocity of 850 ft/s is more like a baseball with a velocity of 61 mph.

The average baseball weighs around 142 grams which converts to about 2,187 grains. 61 mph converts to 89.47 ft/s. Multiply them together and you get 195,643 grains*ft/s.

For the bullet, a 230 gr projectile at 850 ft/s gives you a momentum of 195,500 grains*ft/s.

When I did the calculation over a year ago, I was probably calculating that at most it's like an 80mph fastball.

Using upper end 230 45acp +P can go 1134 fps at close range.

Do a replace ratio on your calculation...

61 mph X (1134/850 fps) = 81 mph

You can find 45 ACP in a wide range of velocities.
850 fps is on the lower end on cheap target ammo.

https://www.buffalobore.com/images/eb_45-230_1200fps.png

AeroEngi
11-21-2012, 5:00 PM
When I did the calculation over a year ago, I was probably calculating that at most it's like an 80mph fastball.

Using upper end 230 45acp +P can go 1134 fps at close range.

Do a replace ratio on your calculation...

61 mph X (1134/850 fps) = 81 mph

You can find 45 ACP in a wide range of velocities.
850 fps is on the lower end on cheap target ammo.

https://www.buffalobore.com/images/eb_45-230_1200fps.png

Oh nice! I didn't even think about that. I was just using numbers for standard 230 gr .45 acp. Either way, knockdown power is pretty insignificant.

Sent from my DROID RAZR using Tapatalk 2

AeroEngi
11-21-2012, 5:07 PM
Don't waste your time trying explain to people on here basic known scientific facts like Newton's laws. They have it firmly set in their minds from watching Hollywood TV shows & movies, that .40 and up pistol rounds posses tremendous knock down power. Powerful enough to lift you off your feet & throw you backwards. Enough power to toss around a 250lb person, yet can somehow be easily fired with one hand. They also wrongly believe that hollow point rounds enhance knock down power.

In the real world you can watch Richard Davis get shot with pistols, shotguns & rifles multiple time while wearing his 2nd chance vests, even while standing on one foot & not get thrown to the ground. The movie to watch with those scenes is called: Deadly Weapons: Firearms & Firepower from 1985.

o5f1Fo4r4_I

Actually, hollow points could enhance knockdown power. A hollow point will transfer most if not all of it's momentum into it's target. A standard round nose projectile will likely exit it's target out the back and not transfer all it's momentum into the target.

Marthor
11-21-2012, 5:22 PM
http://www.youtube.com/watch?v=ged4lz_Fw2Y&feature=youtube_gdata_player

Check out the video. You have to go up to a huge caliber rifle (elephant gun) before you get some good "knockdown power".

USMC 82-86
11-21-2012, 6:58 PM
I knew my right cross had more knockdown power than a measly .45. :p

creampuff
11-21-2012, 7:13 PM
True, true.
But an 80mph Fastball, cannot penetrate my body and lodge itself into the CNS, which could result in an instant knockdown.

Well, unless the fastball hit me right in the temple...umm never mind.

This is too cerebral the night before Thanksgiving. I'm going to go back to watching Woody Woodpecker with the kids.

jumbopanda
11-21-2012, 7:21 PM
Guns are meant to punch holes in people, not knock them down. If you want to knock someone down, get a baseball bat.

If you're worried about the effectiveness of a firearm in an self defense scenario, I'll make things simple for you. Just ask yourself two questions:

1. Will this gun penetrate enough tissue to reach vital organs?
2. Will I be able to shoot an assailant in a vital organ?

IVC
11-21-2012, 7:31 PM
You have to define the "knockdown power" before you make any comparisons.

From the physics perspective, you would most commonly talk about either (1) momentum, or (2) energy, or (3) pressure on impact. These are vastly different concepts and comparing them to a baseball ball is at minimum misleading.

Look at momentum first. If you wore a steel plate and got hit by the bullet, you would feel the same as if you got hit by the baseball of the appropriate velocity. Neither would hurt and you wouldn't fly off. But, this is not how the things work.

What matters is the surface area of the projectile, since the pressure at the impact point is inversely proportional to this area. That's why if you get hit behind a steel plate, you feel nothing (very low pressure, since force is applied over large area). If you get hit with the bullet directly, the pressure is so large that it will penetrate your body. This is significantly different than the baseball which has large surface area (due to softness of the body, the area of contact is quite large).

The penetration is what starts the killing process. Once inside the body, the energy starts dissipating while the bullet is traveling through the body and causing damage. At this time, hollow points will expand to ensure (1) larger cavity with potential for bleeding; (2) all energy is used up for causing internal damage by effectively coming to rest inside the body, having shed all of the kinetic energy.

The energy dissipation inside the body is also why FMJ bullets are not suitable for hunting. If there is no direct hit to a vital area, FMJ will travel through the body and exit, having caused very little damage except in the direct path of the bullet.

Take all of this into account and you'll see that it's pretty naive to compare bullets to baseballs. You can match the momentum, but you completely miss the mechanism that causes damage.

therealnickb
11-21-2012, 7:58 PM
This topic comes around now and then and I've read several threads, but I just thought of a new way to think about it that makes sense.

I've read enough threads and done some calculations, to say that a 45 acp has knockdown power similar to an 80 mph fastball... which isn't that much "knockdown power". Knockdown power is generally a myth.

The new way to think about it though is "for every action, there is an equal and opposite reaction". If you fire a weapon that knocks you back on your butt, then yes, that probably has some real "knockdown power". But that's going to be something like an elephant gun, that is hard to manhandle the kickback.

Just thought I'd share. Knockdown power makes more sense to me thinking about it that way. Cheers! :cool:

reel reel reel reel player?

therealnickb
11-21-2012, 7:59 PM
Guns are meant to punch holes in people, not knock them down. If you want to knock someone down, get a baseball bat.

If you're worried about the effectiveness of a firearm in an self defense scenario, I'll make things simple for you. Just ask yourself two questions:

1. Will this gun penetrate enough tissue to reach vital organs?
2. Will I be able to shoot an assailant in a vital organ?

guns don't penetrate.

therealnickb
11-21-2012, 8:30 PM
When you fire your 45 acp gun, you already have a firm grip on the handle.

When you catch the 80mph fastball, you have to eliminate the sting and focus only on how much push force you got from catching it. That's the knockdown power.

1) with a mitt.

2) I've never been "knocked down" by anything smaller than a human.

ClarenceBoddicker
11-21-2012, 11:28 PM
Actually, hollow points could enhance knockdown power. A hollow point will transfer most if not all of it's momentum into it's target. A standard round nose projectile will likely exit it's target out the back and not transfer all it's momentum into the target.

No, as knockdown power from guns that can be fired with a human holding them does not exist. The projectile would have to weigh very close to the target to be able to knock them down.

A hollow point round can certainly enhance stopping power, which is very real unlike knockdown power.

POLICESTATE
11-21-2012, 11:36 PM
About a year ago I ran a poll over which round would people least like to get hit by, .45 ACP, .40 S&W, 9mm. .45 won of course, followed by the .40 and finally the 9mm last. It was done to end the whole "9mm vs .40 vs .45" debate going on at the time. Yeah it was kind of silly but the fact is, you are more likely to get more damage out of a .45 than a 9mm. Also we see the same thing with 5.56mm vs 7.62mm.

In any case, I would much rather take an 80mph baseball to the chest than a .45 ACP to the chest. There is no comparison. One is going to hurt, the other will very likely kill me, or at least come very close.

Strange observations you make there Marthor. Out of curiosity, how do you answer question 11.f. on the ATF Form 4473?

Oh and I should point out that the size of objects in motion and their mass in addition to velocity make a huge difference in what happens when they hit other objects.

A baseball is not a bullet.

patriot_man
11-22-2012, 12:39 AM
So what you're saying is that the energy exerted by a 80 MPH baseball is comparable to the energy exerted by a .45 ACP round?

I'd take a 80 MPH baseball any day over .45 ACP. Quick calculation with a 145 gram baseball at 80 MPH comes out to around 117 Joules, nothing in comparison with any .45 ACP round.

:facepalm:

jumbopanda
11-22-2012, 1:57 AM
guns don't penetrate.

:facepalm:

SB1964
11-22-2012, 2:14 AM
I`ve never Caught a .45 ACP!

Marthor
11-22-2012, 5:23 AM
Take all of this into account and you'll see that it's pretty naive to compare bullets to baseballs. You can match the momentum, but you completely miss the mechanism that causes damage.

We didn't miss anything. As was said earlier, the topic of this thread is "knockdown power".

When comparing the baseball and bullet, we're only talking about knockdown power. We're not talking about penetration or which one does more damage. The 45 acp bullet and baseball both have very small "knockdown power".

the86d
11-22-2012, 5:32 AM
If you are looking for knockdown power, you should keep cinder blocks near the top of the stairs...

FX-05 Xiuhcoatl
11-22-2012, 5:59 AM
:facepalm:

missiontrails
11-22-2012, 10:01 AM
If you want to knock them down, use a baseball bat, if you want to kill them, 9mm with a top quality personal defense round will suffice.

SJgunguy24
11-22-2012, 10:24 AM
I stand by my earlier post, "knockdown power" is not the job for a bullet. You bleed them dead, shut down the brain, or severe trauma to vital organs.

You also cannot compare a .45acp slug with a baseball. The bullet is less than 1/2 an inch accross and a baseball is close to 3" accross. To get a baseball to punch through a human body like a bullet, it's gonna need to go way faster than 80 mph.
Think cross section.

patriot_man
11-22-2012, 10:43 AM
I stand by my earlier post, "knockdown power" is not the job for a bullet. You bleed them dead, shut down the brain, or severe trauma to vital organs.

You also cannot compare a .45acp slug with a baseball. The bullet is less than 1/2 an inch accross and a baseball is close to 3" accross. To get a baseball to punch through a human body like a bullet, it's gonna need to go way faster than 80 mph.
Think cross section.

this

Freq18Hz
11-22-2012, 10:44 AM
Don't waste your time trying explain to people on here basic known scientific facts like Newton's laws. They have it firmly set in their minds from watching Hollywood TV shows & movies, that .40 and up pistol rounds posses tremendous knock down power. Powerful enough to lift you off your feet & throw you backwards. Enough power to toss around a 250lb person, yet can somehow be easily fired with one hand. They also wrongly believe that hollow point rounds enhance knock down power.

In the real world you can watch Richard Davis get shot with pistols, shotguns & rifles multiple time while wearing his 2nd chance vests, even while standing on one foot & not get thrown to the ground. The movie to watch with those scenes is called: Deadly Weapons: Firearms & Firepower from 1985.

o5f1Fo4r4_I

I'd like to see him stand after taking a 45-70 to the chest at that range.

-Freq

Tarn_Helm
11-22-2012, 10:58 AM
. . . Knockdown power is generally a myth. . . .

Yep.

Though I prefer to think of knockdown power as "urban legend" rather than "myth."

Witnesses get confused when they see a person react to having been shot.

The bullet recipient sometimes jerks violently, to the extent that s/he reacts at all.

But this is no different from the violent aversive reaction to having been burnt by a hot stove, which has no "knockdown power." But people who touch it still sometimes jerk away violently from it.

The perception that bullets knock down their recipients results from a post hoc ergo propter hoc fallacy in reasoning.
:cool:

Cheap Shot
11-22-2012, 10:59 AM
I wish they made a caliber that had the same knock down power as Chuck Norris.

SIG WORTHY!!! :D

AeroEngi
11-22-2012, 11:39 AM
No, as knockdown power from guns that can be fired with a human holding them does not exist. The projectile would have to weigh very close to the target to be able to knock them down.

A hollow point round can certainly enhance stopping power, which is very real unlike knockdown power.

Sorry, I meant stopping power in my earlier post. Thanks for the correction.

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